Field of the Invention
The present invention concerns a method to generate image data based on magnetic resonance thermometry data; an image data generation unit to generate image data on the basis of magnetic resonance thermometry data; a medical imaging system with such an image data generation unit; and a medical imaging system with an ablation system.
Description of the Prior Art
“Thermometry” designates the science of temperature measurement or generally methodology for determining temperatures, and in particular spatial and/or temporal temperature distributions. In medicine, thermometry is used in numerous ways. Some of these medical applications require thermometric detection and the depiction of regions of the inside of a patient (examination subject).
One known method for thermometric detection of regions of the interior of a patient is the generation of magnetic resonance thermometry data (abbreviated in the following as MR thermometry data). The thermally dependent change of magnetic resonance measurement values is determined with a magnetic resonance system. For example, the longitudinal relaxation time of hydrogen protons, the molecular diffusion coefficient of hydrogen protons, and the shift of the magnetic resonance frequency of hydrogen protons, are suitable magnetic resonance measurement values for this purpose. Various methods to generate MR thermometry data are described in the article “Magnetic resonance temperature imaging” (Int. J. Hyperthermia, September 2005; 21(6): 515-531) by B. Denis de Senneville, for example.
In the generation of “real-time thermometry image data” or “live thermometry image data” from measured thermometry data, the measurement and depiction of MR thermometry data takes place from which thermometry image data can be reconstructed for further presentation, preferably with a relatively low spatial resolution. The low spatial resolution enables an accelerated measurement, calculation and generation of a presentation of the MR thermometry data, and thus a relatively high “temporal resolution”. For example, a “real-time reconstruction” or “live reconstruction” of MR thermometry data can take place with sufficient spatial resolution when the underlying measurements take place at a frequency of more than two images per second (preferably more than five images per second), with the raw magnetic resonance data on which the respective images are based being acquired at different time periods.
Although the low spatial resolution of the live thermometry image data is well-suited for thermometry, practical usage of the live images in the everyday clinical environment is difficult. Many applications require additional information that can be identified only with difficulty—or that is not included at all—in the live images.